/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include "uv.h"
#include "internal.h"
#include "heap-inl.h"

#include <assert.h>
#include <limits.h>

static int timer_less_than(const struct heap_node* ha,
    const struct heap_node* hb)
{
    const uv_timer_t* a;
    const uv_timer_t* b;

    a = container_of(ha, const uv_timer_t, heap_node);
    b = container_of(hb, const uv_timer_t, heap_node);

    if (a->timeout < b->timeout)
        return 1;
    if (b->timeout < a->timeout)
        return 0;

    /* Compare start_id when both have the same timeout. start_id is
   * allocated with loop->timer_counter in uv_timer_start().
   */
    if (a->start_id < b->start_id)
        return 1;
    if (b->start_id < a->start_id)
        return 0;

    return 0;
}

int uv_timer_init(uv_loop_t* loop, uv_timer_t* handle)
{
    uv__handle_init(loop, (uv_handle_t*)handle, UV_TIMER);
    handle->timer_cb = NULL;
    handle->repeat = 0;
    return 0;
}

int uv_timer_start(uv_timer_t* handle,
    uv_timer_cb cb,
    uint64_t timeout,
    uint64_t repeat)
{
    uint64_t clamped_timeout;

    if (cb == NULL)
        return -EINVAL;

    if (uv__is_active(handle))
        uv_timer_stop(handle);

    clamped_timeout = handle->loop->time + timeout;
    if (clamped_timeout < timeout)
        clamped_timeout = (uint64_t)-1;

    handle->timer_cb = cb;
    handle->timeout = clamped_timeout;
    handle->repeat = repeat;
    /* start_id is the second index to be compared in uv__timer_cmp() */
    handle->start_id = handle->loop->timer_counter++;

    heap_insert((struct heap*)&handle->loop->timer_heap,
        (struct heap_node*)&handle->heap_node,
        timer_less_than);
    uv__handle_start(handle);

    return 0;
}

int uv_timer_stop(uv_timer_t* handle)
{
    if (!uv__is_active(handle))
        return 0;

    heap_remove((struct heap*)&handle->loop->timer_heap,
        (struct heap_node*)&handle->heap_node,
        timer_less_than);
    uv__handle_stop(handle);

    return 0;
}

int uv_timer_again(uv_timer_t* handle)
{
    if (handle->timer_cb == NULL)
        return -EINVAL;

    if (handle->repeat) {
        uv_timer_stop(handle);
        uv_timer_start(handle, handle->timer_cb, handle->repeat, handle->repeat);
    }

    return 0;
}

void uv_timer_set_repeat(uv_timer_t* handle, uint64_t repeat)
{
    handle->repeat = repeat;
}

uint64_t uv_timer_get_repeat(const uv_timer_t* handle)
{
    return handle->repeat;
}

int uv__next_timeout(const uv_loop_t* loop)
{
    const struct heap_node* heap_node;
    const uv_timer_t* handle;
    uint64_t diff;

    heap_node = heap_min((const struct heap*)&loop->timer_heap);
    if (heap_node == NULL)
        return -1; /* block indefinitely */

    handle = container_of(heap_node, const uv_timer_t, heap_node);
    if (handle->timeout <= loop->time)
        return 0;

    diff = handle->timeout - loop->time;
    if (diff > INT_MAX)
        diff = INT_MAX;

    return diff;
}

void uv__run_timers(uv_loop_t* loop)
{
    struct heap_node* heap_node;
    uv_timer_t* handle;

    for (;;) {
        heap_node = heap_min((struct heap*)&loop->timer_heap);
        if (heap_node == NULL)
            break;

        handle = container_of(heap_node, uv_timer_t, heap_node);
        if (handle->timeout > loop->time)
            break;

        uv_timer_stop(handle);
        uv_timer_again(handle);
        handle->timer_cb(handle);
    }
}

void uv__timer_close(uv_timer_t* handle)
{
    uv_timer_stop(handle);
}
